“Six out of the last 10 Januarys have been down and there is some feeling that people are taking more notice of tax strategies,” Cashin told CNBC.

“There wasn’t an awful lot of tax selling this year, although we had a very significant rally from March.”

Cashin said the markets are reminiscent of the rally in 2003.

“[The rally] ran from late February into year-end and it lasted a bit into January or so, and then we had a pullback after that,” he said. “So we’re still waiting to see. I’m stubbornly concerned that they are overvalued—there is a feeling that it’s 'Nasdaq 4,000.'”